The beamforming algorithm 骣 minw Rw+ mjnw'ER+ Etr(R w KL 沙KL st. cw= s.t. Cw wopr=RoC(Croc)f the trace of r: two inverse matrices; three matrix- products and one matrix-vector production (過学故时大学 A Direct Numerical Imaging Method 30 National University of Defense TechnologyA Direct Numerical Imaging Method The beamforming algorithm 30 2 2 2 min + T K L d v v v v v w w R w w x . 1 s t. . 轾 = 犏犏犏臌 0 v C w 2 m ni + ( ) T t r K L 骣ç d ÷ ç ÷ ç ÷ ç桫 ÷ v v v w w w R R I . 1 s t. . 轾 = 犏犏犏臌 0 v C w ( ) 1 1 1 = T opt - v % % - - w R C C R C f • the trace of R; • two inverse matrices; • three matrix – products and one matrix-vector production